There continues to be an increasing demand for computing devices, and a demand for increased performance of the computing devices. While there is demand for higher-performance devices, there is also a great demand for lower-power devices. In low-power devices, the interaction among components on the device consumes much of the device power. The interaction among components can generally be referred to as I/O (input/output), where components exchange information.
Most active power in component I/O is used by the output driver. Systems currently have a very limited ability to adjust the power consumption of the I/O circuits. Typically, I/O circuits use a fixed voltage swing whose value is based on a worst-case setting. Even assuming there was a better option setting that could use lower power in a particular device, there are currently limited options available to adjust the I/O power settings. Furthermore, it will be understood that changing I/O settings to reduce power consumption can result in inefficiencies manifesting themselves in other ways that can offset the gains obtained by changing the settings.
One issue encountered by current efforts to reduce I/O power use is that the voltage swing and driver output impedance (Ron) are not independent of each other. Thus, current efforts to adjust Ron (either statically or dynamically) to reduce I/O power result in signal integrity degradation, which means that the memory I/O power can be reduced, but more power is used in other system components to counter the loss of signal integrity. The overall system perspective is minimal to no power reduction by adjusting Ron.
Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the inventive concepts presented herein.